Metabolic clearance rate in sheep of a met-enkephalin analogue estimated by radioimmunoassay.
A sensitive and specific radioimmunoassay developed for measuring the met-enkephalin analogue d-ala2-met(0)5-ol-enkephalin (DAMME) was used to study the pharmacokinetics of DAMME in the circulation of sheep. Plasma concentrations of DAMME were measured at varying time-intervals after an intravenous bolus injection or following a constant intravenous infusion of the analogue. The mean metabolic clearance rate of DAMME was 2.8 ml/min per kg, the mean circulating half-life was 52 min and the mean volume of distribution was 190 ml/kg. The longer circulating time of the analogue when compared with that of naturally occurring met-enkephalin would appear to explain its prolonged analgesic effect.
D000818:Animals; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin; D004723:Endorphins / Q000378:metabolism*; D004745:Enkephalins / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008657:Metabolic Clearance Rate; D011863:Radioimmunoassay; D012756:Sheep
D004723:Endorphins; D004745:Enkephalins; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin; D013007:Growth Hormone-Releasing Hormone